Research On Ground Penetrating Radar Accurate Identification Of Tunnel Lining Defects

After decades of development,China's economic construction and scientific and technological level have greatly improved,and large-scale construction has been carried out in the field of transportation.During the service period,the tunnel lining will be affected by the seepage erosion of surrounding rocks and other various disasters of different causes,which will cause hidden dangers to the quality and safety of the project,which will seriously threaten the public.Therefore,the quality of tunnel linings is getting more and more attention.How to detect these places more effectively has become the first issue for people to consider.Therefore,the application of ground penetrating radar has attracted more and more attention from the society.It is still difficult to accurately determine the disease characteristics in the ground radar image.Based on the introduction of ground penetrating radar and data image information processing,this paper uses the finite difference time-domain method to simulate the tunnel lining structure and disease.Based on the actual situation of the tunnel lining structure,this paper establishes four types of models for designing the hollow lining,the water-filled cavity,the thickness of the second lining and the steel bars.Using numerical simulation,four types of wavelength response characteristics are obtained.Ground penetrating radar is used to inspect the lining quality of the actual tunnel,and the image characteristics of the voids,water-filled voids,the thickness of the second lining,and the distribution of the steel bars in the test results are analyzed and studied.Aiming at the problem that the defect features in radar detection images are not obvious,an improved algorithm based on Canny operator is proposed,which uses Butterworth bandpass filtering to filter and denoise the original image,and reduces the information in the radar image by controlling the cutoff frequency At last,edge detection is performed on the GPR recording profile based on the iterative threshold.Combined with the analysis results in numerical simulation and actual detection,it is verified that the method can effectively guide the actual detection work.Due to the influence of many factors,the Canny edge detection algorithm we used in this article has a lot of room for improvement in the radar signal exploration,which needs to be further studied in future work.